期刊文献+
共找到16篇文章
< 1 >
每页显示 20 50 100
Association of accelerometer-measured sleep duration and different intensities of physical activity with incident type 2 diabetes in a population-based cohort study 被引量:2
1
作者 Xinyi Jin yilin chen +8 位作者 Hongliang Feng Mingqing Zhou Joey W.Y.Chang Yaping Liu Alice Pik Shan Kong Xiao Tan Yun-Kwok Wing Yannis Yan Liang Jihui Zhang 《Journal of Sport and Health Science》 SCIE CAS CSCD 2024年第2期222-232,共11页
Purpose:The aim of the current study was to investigate the association of accelerometer-measured sleep duration and different intensities of physical activity(PA)with the risk of incident type 2 diabetes in a populat... Purpose:The aim of the current study was to investigate the association of accelerometer-measured sleep duration and different intensities of physical activity(PA)with the risk of incident type 2 diabetes in a population-based prospective cohort study.Methods:Altogether,88,000 participants(mean age=62.2±7.9 years,mean±SD)were included from the UK Biobank.Sleep duration(short:<6 h/day;normal:6-8 h/day;long:>8 h/day)and PA of different intensities were measured using a wrist-won accelerometer over a 7-day period between 2013 and 2015.PA was classified according to the median or World Health Organization-recommendation:total volume of PA(high,low),moderate-to-vigorous PA(MVPA)(recommended,not recommended),and light-intensity PA(high,low).Incidence of type 2diabetes was ascertained using hospital records or death registries.Results:During a median follow-up of 7.0 years,1615 incident type 2 diabetes cases were documented.Compared with normal sleep duration,short(hazard ratio(HR)=1.21,95%confidence interval(95%CI):1.03-1.41)but not long sleep duration(HR=1.01,95%CI:0.89-1.15)was associated with excessive type 2 diabetes risk.This increased risk among short sleepers seems to be protected against by PA.Compared with normal sleepers with high or recommended PA,short sleepers with low volume of PA(HR=1.81,95%CI:1.46-2.25),not recommended(below the World Health Organization-recommended level of)MVPA(HR=1.92,95%CI:1.55-2.36),or low light-intensity PA(HR=1.49,95%CI:1.13-1.90)had a higher risk of type 2 diabetes,while short sleepers with a high volume of PA(HR=1.14,95%CI:0.88-1.49),recommended MVPA(HR=1.02,95%CI:0.71-1.48),or high light-intensity PA(HR=1.14,95%CI:0.92-1.41)did not.Conclusion:Accelerometer-measured short but not long sleep duration was associated with a higher risk of incident type 2 diabetes.A higher level of PA,regardless of intensity,potentially ameliorates this excessive risk. 展开更多
关键词 Light physical activity Sleep duration Triaxial accelerometer Type 2 diabetes UK Biobank
下载PDF
Effects of Different Seasons on Cutting Propagation of Five Citrus Rootstocks
2
作者 Liying GUO Yun chen +5 位作者 Meiling LI yilin chen Wenwen HUANG Yuanmeng YU Guochan HUANG Qianhua JI 《Asian Agricultural Research》 2024年第11期29-35,43,共8页
[Objectives]To explore the cutting propagation mode of citrus rootstock,improve the survival rooting rate of citrus rootstock,and provide theoretical guidance and technical reference for the rooting research of diffic... [Objectives]To explore the cutting propagation mode of citrus rootstock,improve the survival rooting rate of citrus rootstock,and provide theoretical guidance and technical reference for the rooting research of difficult-to-root plants such as citrus.[Methods]Five citrus rootstocks Citrus tangerina Tanaka‘Hongju’,Citrus haniana Hort‘Suanju’,Citrus limonia Osbeck‘Hongningmeng’,Citrus sinensis×Poncirus trifoliata‘Zhicheng’and Poncirus trifoliate(L)Raf.‘Zhike’were used as experimental materials to select the suitable cutting substrate for citrus rootstocks by measuring the physical properties of the substrate.Cutting was carried out in spring,summer,autumn and winter respectively.After cutting,the morphological changes of cuttings were observed regularly,and the callus rate,germination rate and rooting rate of cuttings were recorded.[Results]The best substrate for citrus rootstock cutting was peat soil,vermiculite and fine river sand(2:1:1).The callus of citrus rootstock in different cutting seasons began to appear in 10-22 d,and the callus rate reached 55%-100%.In terms of budding,the budding time was the earliest in summer and autumn,and slightly later in spring and winter;the germination rate of C.limonia Osbeck‘Hongningmeng’was the highest,and the germination rate of C.sinensis×P.trifoliata‘Zhicheng’and P.trifoliate(L)Raf.‘Zhike’was lower;in terms of rooting,C.limonia Osbeck‘Hongningmeng’had the earliest rooting time and the highest rooting rate and could reach 100%in all seasons;the rooting rate of C.tangerina Tanaka‘Hongju’was 50%-80%;the rooting rate of C.haniana Hort‘Suanju’was 60%-80%;C.sinensis×P.trifoliata‘Zhicheng’and P.trifoliate(L)Raf.‘Zhike’showed the earliest rooting time and the highest rooting rate in summer,and the latest rooting time and the lowest rooting rate in winter,which were only 14.5%.Therefore,different citrus rootstock varieties should choose the appropriate cutting time according to their own characteristics.[Conclusions]The results of this study can provide a scientific basis for a large number of cutting propagation of different citrus rootstocks,and have practical guiding significance for large-scale planting. 展开更多
关键词 CITRUS Cutting propagation Rooting rate VARIETIES
下载PDF
Atp6i deficient mouse model uncovers transforming growth factor-β1/Smad2/3 as a key signaling pathway regulating odontoblast differentiation and tooth root formation 被引量:1
3
作者 Jue Wang Abigail McVicar +4 位作者 yilin chen Hong-Wen Deng Zhihe Zhao Wei chen Yi-Ping Li 《International Journal of Oral Science》 SCIE CAS CSCD 2023年第3期390-400,共11页
The biomolecular mechanisms that regulate tooth root development and odontoblast differentiation are poorly understood.We found that Atp6i deficient mice(Atp6i^(−/−))arrested tooth root formation,indicated by truncate... The biomolecular mechanisms that regulate tooth root development and odontoblast differentiation are poorly understood.We found that Atp6i deficient mice(Atp6i^(−/−))arrested tooth root formation,indicated by truncated Hertwig’s epithelial root sheath(HERS)progression.Furthermore,Atp6i deficiency significantly reduced the proliferation and differentiation of radicular odontogenic cells responsible for root formation.Atp6i^(−/−)mice had largely decreased expression of odontoblast differentiation marker gene expression profiles(Col1a1,Nfic,Dspp,and Osx)in the alveolar bone.Atp6i^(−/−)mice sample RNA-seq analysis results showed decreased expression levels of odontoblast markers.Additionally,there was a significant reduction in Smad2/3 activation,inhibiting transforming growth factor-β(TGF-β)signaling in Atp6i^(−/−)odontoblasts.Through treating pulp precursor cells with Atp6i^(−/−)or wild-type OC bone resorption-conditioned medium,we found the latter medium to promote odontoblast differentiation,as shown by increased odontoblast differentiation marker genes expression(Nfic,Dspp,Osx,and Runx2).This increased expression was significantly blocked by anti-TGF-β1 antibody neutralization,whereas odontoblast differentiation and Smad2/3 activation were significantly attenuated by Atp6i^(−/−)OC conditioned medium.Importantly,ectopic TGF-β1 partially rescued root development and root dentin deposition of Atp6i^(−/−)mice tooth germs were transplanted under mouse kidney capsules.Collectively,our novel data shows that the prevention of TGF-β1 release from the alveolar bone matrix due to OC dysfunction may lead to osteopetrosis-associated root formation via impaired radicular odontoblast differentiation.As such,this study uncovers TGF-β1/Smad2/3 as a key signaling pathway regulating odontoblast differentiation and tooth root formation and may contribute to future therapeutic approaches to tooth root regeneration. 展开更多
关键词 SMAD2/3 IMPAIRED prevention
下载PDF
Social isolation, loneliness and subsequent risk of major adverse cardiovascular events among individuals with type 2 diabetes mellitus 被引量:1
4
作者 Yannis Yan Liang yilin chen +7 位作者 Hongliang Feng Huachen Xue Yu Nie Qi-Yong H Ai Jiacheng Ma Lulu Yang Jihui Zhang Sizhi Ai 《General Psychiatry》 CSCD 2023年第6期481-490,共10页
Background Individuals with type 2 diabetes mellitus(T2DM)are more vulnerable to social disconnection compared with the general population;however,there are few relevant studies investigating this issue.Aims To invest... Background Individuals with type 2 diabetes mellitus(T2DM)are more vulnerable to social disconnection compared with the general population;however,there are few relevant studies investigating this issue.Aims To investigate whether social isolation or loneliness may be associated with subsequent risk of developing major adverse cardiovascular events,whether these associations vary according to fatal and non-fatal outcomes and how behavioural,psychological and physiological factors mediate these associations.Methods This longitudinal analysis included data from 19360 individuals with T2DM at baseline(2006-2010)from the UK Biobank.Social isolation and loneliness were measured using self-report questionnaires.The study outcomes included the first events of myocardial infarction(MI)or stroke(n=2273)and all-cause(n=2820)or cardiovascular disease-related mortality through linked hospital data ordeath registries.Results Over a median follow-up of 12.4 years(interquartile range(IQR):11.6-13.3 years),participants who were more socially isolated(most social isolation vs least social isolation)experienced increased risks for all-cause(hazard ratio(HR):1.33,95%confidence interval(Cl):1.19 to 1.47)and cardiovascular disease(HR:1.36,95%Cl:1.17 to 1.59)mortality but not first Ml or stroke.Loneliness(yes vs no)was associated with a greater risk for a composite of incident MI or stroke(HR:1.37,95%Cl:1.19 to 1.57)but not mortality.Social isolation was associated with fatal Ml and stroke,whereas loneliness was associated with non-fatal Ml and stroke.The significant associations of social isolation and loneliness with outcomes were mainly mediated by behavioural factors(mediating proportion:17.8%-28.2%and 17.6%-17.8%,respectively).Conclusions Among individuals with T2DM,social isolation and loneliness are associated with a greater risk of developing major adverse cardiovascular events,with differences in both risks stratified according to fatal and non-fatal events and underlying mediating factors. 展开更多
关键词 CARDIOVASCULAR MORTALITY MELLITUS
下载PDF
The Function of GABA in Plant Cell Growth, Development and Stress Response 被引量:1
5
作者 Yue Jin Lulu Zhi +3 位作者 Xin Tang yilin chen John T.Hancock Xiangyang Hu 《Phyton-International Journal of Experimental Botany》 SCIE 2023年第8期2211-2225,共15页
Gamma-aminobutyric acid(GABA)is a ubiquitous four-carbon non-protein amino acid that is involved in various physiological processes of plant growth and development,such as root architecture,stem elongation,leaf senesc... Gamma-aminobutyric acid(GABA)is a ubiquitous four-carbon non-protein amino acid that is involved in various physiological processes of plant growth and development,such as root architecture,stem elongation,leaf senescence,pollen tube growth,fruit ripening,and seed germination.GABA is also related to plant stress responses,such as drought,salt,cold,and heat stresses.Regulation of GABA in plant stress responses is complex and involves multiple signaling pathways,including calcium and hormone signaling.This paper systematically reviews the synthesis,metabolic pathways and regulatory role of GABA in plants,which will provide new insights into the understanding of plant growth and stress responses and offer novel strategies for improving crop productivity and stress. 展开更多
关键词 GABA STRESS growth and development
下载PDF
Improved RF power performance of InAlN/GaN HEMT by optimizing rapid thermal annealing process for high-performance low-voltage terminal applications
6
作者 周雨威 宓珉瀚 +9 位作者 王鹏飞 龚灿 陈怡霖 陈治宏 刘捷龙 杨眉 张濛 朱青 马晓华 郝跃 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第12期474-480,共7页
Improved radio-frequency(RF)power performance of InAlN/GaN high electron mobility transistor(HEMT)is achieved by optimizing the rapid thermal annealing(RTA)process for high-performance low-voltage terminal application... Improved radio-frequency(RF)power performance of InAlN/GaN high electron mobility transistor(HEMT)is achieved by optimizing the rapid thermal annealing(RTA)process for high-performance low-voltage terminal applications.By optimizing the RTA temperature and time,the optimal annealing condition is found to enable low parasitic resistance and thus a high-performance device.Besides,compared with the non-optimized RTA HEMT,the optimized one demonstrates smoother ohmic metal surface morphology and better heterojunction quality including the less degraded heterojunction sheet resistance and clearer heterojunction interfaces as well as negligible material out-diffusion from the barrier to the channel and buffer.Benefiting from the lowered parasitic resistance,improved maximum output current density of 2279 mA·mm^(-1)and higher peak extrinsic transconductance of 526 mS·mm^(-1)are obtained for the optimized RTA HEMT.In addition,due to the superior heterojunction quality,the optimized HEMT shows reduced off-state leakage current of 7×10^(-3)mA·mm^(-1)and suppressed current collapse of only 4%,compared with those of 1×10^(-1)mA·mm^(-1)and 15%for the non-optimized one.At 8 GHz and V_(DS)of 6 V,a significantly improved power-added efficiency of 62%and output power density of 0.71 W·mm^(-1)are achieved for the optimized HEMT,as the result of the improvement in output current,knee voltage,off-state leakage current,and current collapse,which reveals the tremendous advantage of the optimized RTA HEMT in high-performance low-voltage terminal applications. 展开更多
关键词 InAlN/GaN rapid thermal annealing low voltage RF power performance terminal applications
下载PDF
Phosphorene-Based Heterostructured Photocatalysts 被引量:3
7
作者 Yun Zheng yilin chen +2 位作者 Bifen Gao Bizhou Lin Xinchen Wang 《Engineering》 SCIE EI 2021年第7期991-1001,共11页
Semiconductor photocatalysis is a potential pathway to solve the problems of global energy shortage and environmental pollution.Black phosphorus(BP)has been widely used in the field of photocatalysis owing to its feat... Semiconductor photocatalysis is a potential pathway to solve the problems of global energy shortage and environmental pollution.Black phosphorus(BP)has been widely used in the field of photocatalysis owing to its features of high hole mobility,adjustable bandgap,and wide optical absorption range.Nevertheless,pristine BP still exhibits unsatisfactory photocatalytic activity due to the low separation efficiency of photoinduced charge carriers.In recent years,the construction of heterostructured photocatalysts based on BP has become a research hotspot in photocatalysis with the remarkable improvement of photoexcited charge-separation efficiency.Herein,progress on the design,synthesis,properties,and applications of BP and its corresponding heterostructured photocatalysts is summarized.Furthermore,the photocatalytic applications of BP-based heterostructured photocatalysts in water splitting,pollutant degradation,carbon dioxide reduction,nitrogen fixation,bacterial disinfection,and organic synthesis are reviewed.Opportunities and challenges for the exploration of advanced BP-based heterostructured photocatalysts are presented.This review will promote the development and applications of BP-based heterostructured photocatalysts in energy conversion and environmental remediation. 展开更多
关键词 Phosphorene HETEROSTRUCTURE PHOTOCATALYSIS Water splitting Pollutant degradation
下载PDF
Supramolecular electrostatic self-assembly of mesoporous thin-walled graphitic carbon nitride microtubes for highly efficient visible-light photocatalytic activities 被引量:1
8
作者 yilin chen Xingchen He +5 位作者 Dongsheng Guo Yanqin Cai Jingling chen Yun Zheng Bifen Gao Bizhou Lin 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2020年第10期214-223,共10页
For efficient solar energy conversion,the morphology engineering of hollow graphitic carbon nitride(gC3 N4)is one of the promising approachs benefiting from abundant exposed active sites and short photocarrier transpo... For efficient solar energy conversion,the morphology engineering of hollow graphitic carbon nitride(gC3 N4)is one of the promising approachs benefiting from abundant exposed active sites and short photocarrier transport distances,but is difficult to control on account of easy structural collapse.Herein,a facile supramolecular electrostatic self-assembly strategy has been developed for the first time to fabricate mesoporous thin-walled g-C3N4 microtubes(mtw-CNT)with shell thickness of ca.13 nm.The morphological control of g-C3N4 enhances specific surface area by 12 times,induces stronger optical absorption,widens bandgap by 0.18 e V,improves photocurrent density by 2.5 times,and prolongs lifetimes of charge carriers from bulk to surface,compared with those of bulk g-C3N4.As a consequence,the transformed g-C3N4 exhibits the optimum photocatalytic H2-production rate of 3.99 mmol·h^-1·g^-1(λ>420 nm)with remarkable apparent quantum efficiency of 8.7%(λ=420±15 nm)and long-term stability.Moreover,mtw-CNT also achieves high photocatalytic CO2-to-CO selectivity of 96%(λ>420 nm),much better than those on the most previously reported porous g-C3N4 photocatalysts prepared by the conventional hard-templating and soft-templating methods. 展开更多
关键词 Graphitic carbon nitride Thin wall Mesoporous microtube H2 production CO2 reduction Photocatalysis
下载PDF
Putrescine Enhances Seed Germination Tolerance to Heat Stress in Arabidopsis thaliana 被引量:1
9
作者 Shiyan Lu Yulan Hu +4 位作者 yilin chen Yaru Yang Yue Jin Ping Li Xiangyang Hu 《Phyton-International Journal of Experimental Botany》 SCIE 2022年第9期1879-1891,共13页
Putrescine(Put)as the compound of plant polyamines is catalyzed by arginine decarboxylase(ADC),which is encoded by two members,ADC1 and ADC2 in Arabidopsis,and ADC2 is mainly responsible for Put biosynthesis.Accumulat... Putrescine(Put)as the compound of plant polyamines is catalyzed by arginine decarboxylase(ADC),which is encoded by two members,ADC1 and ADC2 in Arabidopsis,and ADC2 is mainly responsible for Put biosynthesis.Accumulated evidence demonstrates the important function of Put in plant growth and development,but its role in regulating seed germination under high temperature(HT)has not been reported yet.SOMNUS(SOM)is the negative regulator for seed germination thermoinhibition by altering downstream gibberellin(GA)and abscisic acid(ABA)metabolism.In this study,we found exogenous application of Put obviously alleviated the inhibition effect of HT on seed germination.Whereas pharmacological inhibition of endogenous Put level reduced seed germination under HT.Consistently,HT induced the rapid accumulation of Put level,and the adc2 mutant defi-ciency in Put biosynthesis also showed more sensitivity to HT stress.Furthermore,we found that the Put signal suppressed the expression of SOM and changed the transcriptional patterns of genes associated with GA/ABA metabolism.Genetic analysis also revealed SOM was epistatic to ADC2 to alter GA/ABA metabolism.Collectively,our finding reveals the novel function of Put in controlling seed germination under HT through SOM,and provides the possibility to develop Put as the innovational regulator for uniform seed germination under HT stress. 展开更多
关键词 PUTRESCINE seed germination heat stress SOM ADC2
下载PDF
Context-Aware Network Embedding via Variation Autoencoders for Link Prediction
10
作者 Long Tian Dejun Zhang +4 位作者 Fei Han Mingbo Hong Xiang Huang yilin chen Yiqi Wu 《国际计算机前沿大会会议论文集》 2018年第1期24-24,共1页
下载PDF
Visual-Based Character Embedding via Principal Component Analysis
11
作者 Linchao He Dejun Zhang +4 位作者 Long Tian Fei Han Mengting Luo yilin chen Yiqi Wu 《国际计算机前沿大会会议论文集》 2018年第1期16-16,共1页
下载PDF
Dynamic Behavior and Vibration Suppression of a Generally Restrained Pre-pressure Beam Structure Attached with Multiple Nonlinear Energy Sinks 被引量:1
12
作者 Yuhao Zhao Jingtao Du +1 位作者 yilin chen Yang Liu 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2023年第1期116-131,共16页
Beam structures are extensively used in many engineering branches.For marine engineering,the ship shafting system is generally simplified as a vibration model with single or multiple beam structures connected by the c... Beam structures are extensively used in many engineering branches.For marine engineering,the ship shafting system is generally simplified as a vibration model with single or multiple beam structures connected by the coupling stiffness.In engineering,multiple nonlinear energy sinks(NESs)can be arranged on the premise of sufficient installation space to ensure their vibration suppression effect.Considering engineering practice,this study investigates the dynamic behavior and vibration suppression of a generally restrained pre-pressure beam structure with multiple uniformly distributed NESs,where the prepressure is typically caused by thrust bearings,installation ways,and others.System governing equations are derived through the generalized Hamiltonian principle and the variational procedure.Dynamic responses of the pre-pressure beam structure are predicted by the Galerkin truncation method.The effect of NESs on dynamic responses and vibration suppression of the pre-pressure beam structure is studied and discussed.Suitable parameters of NESs have a beneficial effect on the vibration suppression at both ends of the pre-pressure beam structure.NESs can modify the vibration frequency and energy transmission characteristics of the vibration system.For different boundary conditions,the optimized parameters of NESs significantly suppress the vibration energy of the pre-pressure beam structure. 展开更多
关键词 Dynamic behaviors Vibration suppression Pre-pressure beam structure Multiple NESs General boundary constraints
原文传递
An efficient GPU-based parallel tabu search algorithm for hardware/software co-design 被引量:5
13
作者 Neng Hou Fazhi He +1 位作者 Yi Zhou yilin chen 《Frontiers of Computer Science》 SCIE EI CSCD 2020年第5期135-152,共18页
Hardware/software partitioning is an essential step in hardware/software co-design.For large size problems,it is difficult to consider both solution quality and time.This paper presents an efficient GPU-based parallel... Hardware/software partitioning is an essential step in hardware/software co-design.For large size problems,it is difficult to consider both solution quality and time.This paper presents an efficient GPU-based parallel tabu search algorithm(GPTS)for HW/SW partitioning.A single GPU kernel of compacting neighborhood is proposed to reduce the amount of GPU global memory accesses theoretically.A kernel fusion strategy is further proposed to reduce the amount of GPU global memory accesses of GPTS.To further minimize the transfer overhead of GPTS between CPU and GPU,an optimized transfer strategy for GPU-based tabu evaluation is proposed,which considers that all the candidates do not satisfy the given constraint.Experiments show that GPTS outperforms state-of-the-art work of tabu search and is competitive with other methods for HW/SW partitioning.The proposed parallelization is significant when considering the ordinary GPU platform. 展开更多
关键词 hardware/software co-design hardware/software partitioning graphics processing unit GPU-based parallel tabu search single kernel implementation kernel fusion strategy optimized transfer strategy
原文传递
Vertically-resolved indoor measurements of air pollution during Chinese cooking 被引量:1
14
作者 Shuxiu Zheng Huizhong Shen +4 位作者 Guofeng Shen yilin chen Jianmin Ma Hefa cheng Shu Tao 《Environmental Science and Ecotechnology》 SCIE 2022年第4期37-45,共9页
Chinese cooking features several unique processes,e.g.,stir-frying and pan-frying,which represent important sources of household air pollution.However,factors affecting household air pollution and the vertical variati... Chinese cooking features several unique processes,e.g.,stir-frying and pan-frying,which represent important sources of household air pollution.However,factors affecting household air pollution and the vertical variations of indoor pollutants during Chinese cooking are less clear.Here,using low-cost sensors with high time resolutions,we measured concentrations of five gas species and particulate matter(PM)in three different sizes at multiple heights in a kitchen during eighteen different Chinese cooking events.We found indoor gas species were elevated by 21%-106%during cooking,compared to the background,and PMs were elevated by 44%-159%.Vertically,the pollutants concentrations were highly variable during cooking periods.Gas species generally showed a monotonic increase with height,while PMs changed more diversely depending on the cooking activity's intensity.Intense cooking,e.g.,stir-frying,pan-frying,or cooking on high heat,tended to shoot PMs to the upper layers,while moderate ones left PMs within the breathing zone.Individuals with different heights would be subject to different levels of household air pollution exposure during cooking.The high vertical variability challenges the current indoor standard that presumes a uniform pollution level within the breathing zone and thus has important implications for public health and policy making. 展开更多
关键词 Indoor air pollution Chinese cooking Vertical distribution Particulate matter
原文传递
Discovery of the largest natural carbon onions on Earth
15
作者 yilin chen Yong QIN +3 位作者 Jiuqing LI Zhuangfu LI Tianyu YANG Ergang LIAN 《Science China Earth Sciences》 SCIE EI CAS CSCD 2022年第9期1736-1750,共15页
The synthesis of carbon onions in the laboratory by various methods is common;however, naturally occurring carbon onions have only been found in a few geological samples on Earth. This study used high-resolution trans... The synthesis of carbon onions in the laboratory by various methods is common;however, naturally occurring carbon onions have only been found in a few geological samples on Earth. This study used high-resolution transmission electron microscopy to identify natural carbon onions in seven intrusion-affected coal samples collected from Permian coal-bearing strata in the Yongan Coalfield, Fujian Province, South China. This study identified the largest natural carbon onions ever recorded on Earth;their outer diameter was ~55 nm. Granite porphyry intrusions and quartz hydrothermal veins are abundant in the Permian coal-bearing strata in this coalfield. All samples collected were tectonically deformed coals with highly developed structural fractures, friction mirror planes, and maximum vitrinite reflectance values of 4.0–9.5%. Natural carbon onions observed in the coal samples had single or multiple cores, with 24–46 graphitic shells characterized by outer diameters of 24–55 nm. The maximum vitrinite reflectance, outer diameter, and graphitic shell number of carbon onions in the intrusion-affected coal were positively correlated, indicating that the carbon onions were secondary products formed during coal metamorphism owing to magmatic intrusion. Our results suggest that carbon onions in intrusion-affected coal are synthesized by chemical vapor deposition. We speculate that natural carbon onions exist mainly in fractures or cavities, similar to vapor-deposited pyrolytic carbon, which is the leading cause of the uneven distribution of carbon onions in intrusion-affected coals in the study area. 展开更多
关键词 Onion-like fullerenes Intrusion-affected coal Chemical vapor deposition HRTEM Coal metamorphism
原文传递
Bisphosphonium salt: an effective photocatalyst for the intramolecular hydroalkoxylation of olefins
16
作者 Hao cheng Xin Wang +3 位作者 Liang Chang yilin chen Lingling Chua Zhiwei Zuo 《Science Bulletin》 SCIE EI CAS CSCD 2019年第24期1896-1901,共6页
A photocatalytic, intramolecular hydroalkoxylation of alkenes has been achieved by utilizing simple and readily available biphosphonium salts as an effective organic photocatalyst. The unique photocatalytic properties... A photocatalytic, intramolecular hydroalkoxylation of alkenes has been achieved by utilizing simple and readily available biphosphonium salts as an effective organic photocatalyst. The unique photocatalytic properties of biphosphonium salt enables facile oxidations of substituted alkenes to facilitate the streamline and regioselective synthesis of a series of saturated cyclic ethers from simple alkenes under mild conditions. 展开更多
关键词 Bisphosphonium salt HYDROALKOXYLATION Photoredox catalysis
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部